4 Drum Yellow Modular accumulation centers offer the ability to create a customized system. As capacity needs increase, use optional Joining Clips to firmly lock units together and expand storage space. Sumps remain separate and clips can be removed for easy repositioning. In applications calling for a continuous sump, optional Sump-to-Sump Drain Kit (includes joining clips and transfer tube), allows centers to be joined together on-site for full compliance to EPA and fire codes when combined sump capacities need to meet. 49 gallons Sump . 49 x 49 x 5.5. High value secondary containment centers are made of up to 100% recycled, durable polyethylene. These handy platforms offer leak protection from drums, pails, batteries, or any other container of hazardous or non-hazardous liquids. Sturdy, removable grates make sump cleaning easy while low profile offers convenience when loading/unloading. Versatile modular design allows you to customize your workspace -- around existing structures, linear style, or over entire floor. Optional Joining Clips and Sump-to-Sump Drain Kit provide a continuous sump for on-site compliance when needed. Accessory Ramp can be located anywhere on any 2-drum or larger Center.